Incandescent electric lamp



Dec. 29, 1931.

A. [IL-DE CASTRQ INCANDESCENT ELECTRIC LAMP Filed July 6, 1929 Patented Dec. 29, 1931 UNITED STATES ADOLPHE D. DE CASTRO, OF NEW YORK, N. Y.

INCANDESCENT ELECTRIC LAMP Application filed July 6, 1929, Serial No. 376,505, and in Poland and Germany September, 1928.

This invention relates to incandescent electric lamps of the kind having two or more filaments and has particular reference to the control of the circuits of such filaments! An object of the present invention is to provide an electric incandescent lamp in which in the event of a filament breaking or burm ing out, a spare or unused filament in the same lamp becomes automatically and instantaneously incandescent.

According to this invention an electric incandescent lamp, is provided with means controlled by the current adapted to open the contact points carrying current'to the upper and lower filaments, causing the lower filament to go out through failure of the thermostat contact point to pass current to the fixed contact point set in'the strip or disk of non-conducting material, leaving the upper filament burning steadily and normally, and to close said contact points in the event of the rupture or burning out of the filament that has been burning letting the current pass through the fixed contact point to the lower filament which quickly lights up and continues to burn steadily.

In carrying out the invention according to this mode any type of electric lamp is pro-.

vided with'two filaments having two currentcarrying leads and one supporting lead, the latter, merely supporting the two filaments but carrying no current, is sealed ofl" outside the screw base. The lead to the lower filament conducts current between the fixed contact point on the non-conducting strip and thelower filament only and gets'into circuit through contact with the contact point on the thermostat element which normally rests on the fixed contact point while its other end, curved, is fixed together with the curved end of the gauge and the free end of the resistance wire of the heating coil or inlay coil, to

the strip of non-conducting material. I

In-the accompanying drawings Figure 1 is a front elevation of the lamp with the de vice insertedfin the base.

' Figure 2 is 'a' diagrammatic side elevation of the wiring circuit inithe lamp. It shows the wire (1) at its lower base contact (2) its jointure (3)' through the strip of non-conbeing .non-conducting material at (11) the bottom of the fixed contact point (12) to )WhlCh is 1o1ned -the terminal of the lower lead (13) supporting lower filament (14) fastened to 50 the free lead (15) which extending upward supports the upper filament (16) su' ported by the 'main current carrying lead 17) the terminal of which is joined to the free end (18) of the heating coil or inlay coil'(7) above which is the gauge (19). The free or cold lead (15) is sealed off outside thebase.

( v Figure 3 is a side elevation of the thermostat fastened to a disk.

Upon connecting the lamp in circuit, the current flows through the wire (1) in the base contact (2) to the jointure (3) through the strip of non-conducting material at (4) through the heating coil or inlay coil (7) to the contact points (9-12) direct to leads (1317) thus lighting both filaments (147-16). The heat generated in the coil or inlay coil (7 causes the thermostat element (8) to lift its contact point (9) from the fixed contact point (12) disconnecting the current from the latter and causing fila nt (14) to go out leaving filament (16) which, fed by the current flowing directly from base (2) through wire (1) to the'heating coil or inlay coil (7 to lead (17) continues to burn normally and steadily. The rising of the thermostat element (8) is halted by the gauge (19) to facilitate an immediate return of the contact point (9) to the fixed contact point (12). Should the filament ('16) breakor burn out the thermostat elethe thermostat has no function other than to I hold the heating inlay in place for the purlustrated in an earlier application, filed by your petitioner on June 14, 1926, Serial No. 115,97 6, and to which this application is a companion application and for which' Pats ent No. 1,758,434: was granted May 13, 1930.

It will be understood that when the lamp of my invention is inserted in the socket the cold thermostat, being in contact with the terminal of the spare filament, the inrushing current lights both filaments. the moment the inlay coil gets heated, which takes place in a few seconds, it causes the thermosensitive element to rise from its contact, thus breaking the circuit with the spare filament, leaving one burning steadily and normally. A gauge to control the rise of the thermostat, facilitates the recontact of the thermostat when the filamentthat is burning breaks or burns out in which case the current finds its way to the spare filament through the cooled thermostat and its contact point.

According to a further alternative. the filament circuits may be controlled by electro-magnetic means in place of the thermostat device. Thus, for example, a switching device may be employed consisting of a movable hinged or spring element of magnetic material and a fixed contact piece (as shown in 11), a small electro-magnet being suitably disposed to act on the movable element and open the switch when the coil of the said magnet is energized. The magnet coil may be connected in circuit in a similar manner to the heating'coil previously described.

It will be'undorstood that the device is not intended to be a means for a flash or flutter light, nor is the object of this improvement in incandescent electric lamps to achieve a retardation of theelectric current in the lamp but a stable, steady light, the actualautomatic relighting of another filament in the same lamp when the one burning suddenly breaks or burns out.

lVhat I claim is:

In an incandescent lamp, a plurality of filaments, a conductor common to the terminal of each of the filaments, a contact device to maintain a continuous current to both filments, a thermostat clement, including a heating coil, connected with the terminal of tact device in circuit with the other'one of i the'filaments, said thermo-responsive conture.

ADOLPHE D. DE CASTRO. 

